Analysis of the conditions for the occurrence of the effect of a minimum of friction in hybrid bearings based on the load separation principle

Abstract

Reliability of rotating machinery is determined to a considerable degree by the bearing units. For several applications the requirements in rotational speed, bearing load and maximal vibration level are so extreme that neither rolling-element bearings nor fluid-film bearings could provide necessary operating characteristics during all regimes of operation. Hybrid bearings, which are a combination of rolling-element and fluid-film bearings, can improve performance characteristics and reliability of the rotor-bearing systems. A hybrid bearing, where a rolling-element bearing and a fluid-film bearing are positioned parallel to the vector of external load (PLEX), has the following advantages compared to a single bearing, whether rolling-element or fluid-film one: increase of life expectancy, load capacity increase, friction reduction, thermal regime enhancement, increase of stiffness, and damping properties. The present paper presents the results of theoretical and numerical research of friction characteristics of PLEX in mixed sliding and rolling friction, i.e. combination of viscous and rolling contact friction, regime. The conditions of minimum friction effect occurrence have been substantiated, and rational relations between characteristics of hybrid rolling-element bearings and fluid-film bearings needed for provision of such effect have been experimentally proven. Finally, the paper presents recommendations regarding design of such hybrid bearings for heavily loaded bearing nodes of rolling mills.

Keywords

Rolling-element bearing fluid-film bearing hybrid bearing friction torque Stribeck curve

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References

Olaru P. Nano-soldering pseudo-composite material to decrease engine bearing failure. In: 16th EDF-PPRIME Workshop Poitiers – FUTUROSCOPE, Behaviour of journal and thrust bearings under transient and mixed lubrication regime, France, 2017, pp.17–18.

Beschastnih

Ravikovich

. Gas bearing of heavy rotor of gas turbine engines. Experience in development and implementation prospects. Vestnik Moskovskogo Aviatsionnogo Instituta 2010; 17: 91–98.

Belousov

Gritsin

. Gas turbine engine disk risk assessment at the design state taking into account random failures. Russian Aeronaut 2013; 56: 359–364.

Hanovich

. Fluid-film bearings and hybrid bearings, Leningrad: Mashgiz, 1960.

Parker RJ, Fleming DP, Anderson WJ, et al. Experimental evaluation of the series-hybrid rolling-element bearing. NASA TN D-7011, 1970, 27 pp.

Butner MF and Murphy BT. Space shuttle main engine long-life bearings. NASACR179455, 1986, 163 pp.

Nielson CE. Hybrid hydrostatic/ball bearings in high-speed turbomachinery. NASA CR-168124, 1982, 386 pp.

Anderson

Fleming

Parker

. The series hybrid bearing - a new high speed bearing concept. ASME J Lubr Technol 1972; 94: 117–124.

Polyakov RN. Improving of dynamics and working life of rotor supports by coupling rolling-element and fluid-film bearings. Doctoral Thesis, Orel State Technical University, Russia, 2005, 154 pp.

10.

Polyakov RN, Pugachev AO and Savin LA. Vibration reduction in rotor systems on hybrid hydrostatic/ball bearings with load separation. In: 9th international conference on motion and vibration control, 2008, p. 90.

11.

Polyakov RN, Pugachev AO and Savin LA. Reliability improvement of rotor supports by combining rolling-element bearings and fluid-film bearings. In: 7th EDF/LMS Poitiers Workshop FUTUROSCOPE, Operational limits of bearing: Improvement of performance trough modeling and experimentation, 2008, pp.K1–K8.

12.

Polyakov

Savin

Shutin

. Reliability improvement of rotor supports by combining rolling-element bearings and fluid-film bearings. Appl Mech Mater 2014; 630: 188–198.

13.

Harnoy A. Composite bearing-rolling element with hydrodynamic journal. MS Thesis, Technion – Israel Institute of Technology, Israel, 1966.

14.

Harnoy

. Bearing design in machinery: Engineering tribology and lubrication, New York: Marcel Dekker, Inc, 2003, pp. 640–640.

15.

Pietsch E. Zur Frage der Kombination von Gleit-und Wälzlagern. Maschinenbautechnik, 5, 1956.

16.

Harris

. Rolling bearing analysis, 5th ed. New York: Wiley-Interscience, 2006.

17.

Cameron A. Basic Lubrication Theory. Longman Group Ltd., London. 1971.

18.

Khonsari MM and Booser ER. Applied Tribology: Bearing Design and Lubrication. New York : John Wiley. 2001.

19.

Szeri A. Fluid film Lubrication: Theory and Design. Cambridge University Press, Cambridge. 2005.

20.

Constantinescu

. Basic relationships in turbulent lubrication and their extension to include thermal effects. Trans ASME, Ser F 1973; 2: 35–43.

21.

Polyakov

Savin

Shutin

. Reliability improvement of rotor supports by combining rolling-element bearings and fluid-film bearings. Appl Mech Mater 2014; 630: 188–198.

22.

Chikhos K. System Analysis in Tribotechnics. Mir Publ., Moscov. 1982.

23.

Shigley

Mischke

. Mechanical engineering design, New York: McGraw-Hill, 1989.

24.

Allgemeiner Maschinenbau und Windenergieanlagenbau, www.sket.de (accessed 1 October 2017).